Hydraulically operated opening and closing device for doors or the like



Oct. 29, 1968 KATUTARO YOKOTA 3,407,593

HYDRAULICALLY OPERATED OPENING AND CLOSING DEVICE FOR DOORS OR THE LIKEFiled Nov. 9, 1966 Fig.1

uvmzwwwzzzzzza V INVENTOR. 18 19 K4 t vraro Ya Kata BY Atprmf)! I UnitedStates Patent() 3,407,598 HYDRAULICALLY OPERATED OPENING AND CLOSINGDEVICE FOR DOORS OR THE LIKE Katutaro Yokota, Tokyo, Japan, assignor toZentsu Denki Kabushiki Kaisha, Tokyo, Japan Filed Nov. 9, 1966, Ser. No.593,128 Claims. (Cl. 60--52) ABSTRACT OF THE DISCLOSURE An hydraulicallyoperated door opening and closing device is shown in which two opposingpistons are rigidly connected by -a piston rod to be reciprocable in acylinder and to define between them an oil chamber. Each piston has twoopposed one-way valves mounted in it. A rotary oil pump is juxtaposed toone end of the cylinder and-is driven by a direct-connected motor. Thepump is connected by two duets with respectively opposite ends of thecylinder. -A by-pass groove is provided in one wall of the cylinder toby-pass oil from one side of a piston to the other during travel of thepistons in the cylinder; and an adjustable throttle valve is provided tocontrol the opening of an exhaust port which connects one end of thecylinder with the duct that leads from the pump to the opposite end ofthe cylinder.

This invention relates to a hydraulically operated opening and closingdevice for doors or the like.

The present invention has as its primary object to provide ahydraulically operated door opening and closing device comprising anoperating cylinder, a pair of pistons fitted to the opposite ends of apiston rod reciprocable therein and each provided with a pair of one wayvalves at the head ends thereof, a hydraulic pump provided adjacent toone end of said cylinder and operative to deliver oil thereto, and amotor for driving said pump; said pairs of one-way valves beingoperable, in response to an opposing force developed in the body to beactuated by the present opening and closing device, to discharge part ofthe pressure oil into an oil chamber formed intermediate said pistons tocirculate freely in the cylinder.

Heretofore, in door opening and closing devices of this kind usinghydraulic pressure or compressed air, those equipped with means tocontrol the speed of displacement of the opening and closing device, inresponse to an haphazard oppOsing force exerted on the door, as when aperson had his hand pinched by the door or bumped thereby, wereexceptional, and such means required much space or complex operatingmechanism.

In contrast with these defects of conventional devices of this kind, thepresent invention provides a door opening and closing device which maybe operated in response to an haphazard opposing force applied to thedoor, to minimize undue force imposed on the hydraulic system and makefor safety, and which may be fitted within a narrow space because of itscompact size.

The present invention will now be described in detail with reference tocertain embodiments thereof as illustrated in the accompanying drawing.

In the drawing:

FIG. 1 is a longitudinal partial sectional view showing an embodiment ofthe hydraulically operated door open ing and closing device according tothe present invention;

FIG. 2 is a transverse section taken on the line 'II-II of FIGyl;

*F-IG. 3 is a transverse section taken on the line III'-'-III of FIG. 1;

FIG. 4 is an explanatory view illustrating somewhat diagrammatically theoperation ofthe hydraulic system according to the present invention; and

3,407,598 Patented Oct. 29, 1968,

Thus an intermediate oil chamber 29 is defined by the pistons 14, 14'and the wall of the cylinder 16, while pressure oil chambers 1 and 17are defined by the head of the left-hand piston 14 and the head of theright-hand piston 14 respectively. Pressure oil is delivered selectivelyto the pressure oil chamber 17 via exhaust port 31 of the rotary pump 32and to the pressure oil chamber 1 via a second exhaust port 21 of thepump 32 and an oil duct 18.

A by-pass 19 for adjusting the flow of oil is provided between the righthand end of cylinder 16 and oil duct 18 and flow of pressure oil fromthe rotary pump 32 is adjustable by screwing the flow-adjusting screw 20into the by-pass 19. As shown in -FIG. 1, a seat 15' for oneway reliefvalve 26 is provided on the head end of the piston 14' and the one-wayrelief valve 26 operable in one direction is provided in the bore 9thereof. In addition, another one-way relief valve 5 operable in theopposite direction is provided on the same side of the piston 14'. Theone-way relief valve 26 is normally biased towards the left by means ofa spring 7 and the force of the spring 7 i s so adjusted that theone-way relief valve 26 associated therewith may be opened by thepercussive force imposed by the pressure oil, or as the oil pressure inthe hydraulic system is raised excessively due to the opposing forcethat may be produced fortuitously as the door is opened or closed, butnot by the normal level of the oil pressure in the hydraulic system. Onthe other hand, the one-way relief valve 5 is normally biased to theright by means of a spring, thereby to block the oil circuit behind thevalve 5. A side opening 8 opening into the intermediate oil chamber 29is provided in the bore 9. A bifurcate lever 11 is connected at itsforked end to a lug 10 formed centrally of the rod 12 and at its otherend to a shaft 28 formed integral with the lever 30 provided externallyof the hydraulic system of the present opening and closing device androtatable to actuate the lever 30. A by-pass groove 13 is provided in asuitable position extending along the internal wall of the cylinder 16over an extent lessthan the spacing between the opposing pistons 14,14'. In designing, the cross-sectional area of the bypass groove is tobe determined suitably by taking the pressure and flow of oil passingtherethrough and the speed of displacemanually reciprocating the lever24 connected to the piston rod 25.

The rotary pump 32 is connected with the operating cylinder 16. In theembodiment illustrated, the pump 32' is connected to the right-hand sideof the operating cylinder 16. In any case, the exhaust port 21 of thepump is connected by duct 18 to the pressure oil chamber 1, and theother exhaust port 31 to the pressure oil chamber 17. The shaft 22 ofthe motor 23 for driving the pump 32 is connected to or formed integralwith the shaft of the pump 32. The oil is circulated in the confinedpath'and the hydraulic driving system and the mechanism to buildhydraulic pressure in the hydraulic driving system constitute a unit.Motor 23 may be a DC motor or AC commutator motor with commutator 35.Its direction of rotation is reversible by cutting over the electricalconnection thereof and reversing the direction of the exciting current.

In FIG. 3, numeral 36 designates a drain plug for pressure oil andnumeral 37 a seat for drain plug 36 formed integral with the operatingcylinder 16.

Explaining the operation of the present opening and closing device withreference to the block view of FIG. 4 and also to FIGS. 5 and 6,pressure oil is delivered from the operating cylinder 16 into thepressure oil chamber 1 via the port 21 and the oil path 18 by rotationin one diretcion of the motor 23 and of the rotor 33 of the pump 32, asshown in FIG. 4 by the arrow marks in the solid lines, and the left-handpiston 14 is displaced to the right.

The bifurcate lever 11 engaging with the lug on the rod 12 is set intomotion, thereby to rotate the shaft 28.

Thus, the lever 30 connected to the outermost end of the shaft 28 isswiveled, and the door 39 connected to the lever 30 through link 41(FIG. 6) may be opened or closed.

If, during the displacement of the piston 14 to the right, a person hashis hand caught by the door 39 or has it bumped thereby, and, as aconsequence, the oil pressure in the oil chamber 1 has been raisedsuddenly, pressure oil in the chamber 1 will force the one-way valve 26open, against the resistance of the spring 7, and escape to theintermediate oil chamber 29. The excessive oil pressure in the chamber 1may thus be reduced, and furthermore, pressure oil Will flow into thechamber 17 via the by-pass groove 13 provided on the cylinder Wall orback into the pump 32 via the one-way relief valve 5, so the oil may becirculated freely irrespective of the rotation of the pump 32. As theintermediate oil chamber 29 has a relatively larger volume, and servesas the oil storage tank, the percussive force exerted by the pressureoil is lessened in passing through the chamber 29 and the oil iscirculated in the system under reduced pressure via the one-way reliefvalve 5..

Even if the door that is being opened or closed hydraulically isretained forcibly for a considerable period of time, the oil will flowin a free state without producing excess percussive force which mayresult in the destruction of the hydraulic system, and the overload thatmay be applied on the pump 32 and the motor 23 may be avoided.

In case pressure flow of oil from the motor 23 and the pump 32 isreversed, as shown by the dotted line arrows of FIG. 4, the pressure ofoil in the chamber 17 will be increased and the piston 14 forced to theleft in much the same way as the piston 14' is forced to the right underthe pressure of oil in the chamber 1. If the opposing force is appliedto the door 39, the one-way relief valves 26, 5 on the opposite side ofthe cylinder will come into operation, and pressure oil will flow in afree state via bypass groove 13, intermediate oil chamber 29, andby-pass 19 for adjusting the flow of oil provided on the same side ofthe cylinder. Hence, the pump 32 and the motor 23 will idle withoutexcessive pressure being developed in the hydraulic system.

The by-pass 19 for adjusting the flow of oil is adjusted to moderatedistribution or relivery of oil to both the pressure oil chambers 1 and17 and control the speed of displacement of the opposing pistons 14, 14irrespective of the constant speed rotation of the pump 32 if theflowadjusting screw is screwed in a proper amount into the by-pass 19.

While the pump 32 as illustrated is a trochoid type rotary pump, it mayalso be a gear pump or other reversible type rotary pump.

FIG. 5 shows in fragmentary plan view the opening and closing deviceaccording to the present invention as applied to an automobile door inwhich the swingable lever is pivooted at one end to the main operatingcylinder 16 and at the other end to the link 41, the outermost end ofthe link 41 being pivoted to the hinge 51 provided to the fixed wallmember 52. If the motor and the pump mounted adjacent to the cylinder 16is rotated, and the outermost end of the lever 30 is moved to the right,the link 41 pivoted to the lever 30 is swiveled and the door 39 isopened as shown by the dotted line. By reversing the above-mentionedoperation, the door 39 may be returned to the former position. In theinitial stage of the door opening operation, the subsidiary swivel lever24, which is here connected by a link 40 with the door lock 38 will comeinto play to release the lock 38. Numeral denotes the door hinge.

FIG. 6 shows an embodiment wherein the present opening and closingdevice is applied to the door of a house or. building. In thisembodiment, the operating cylinder along with the driving motor and thepump is attached as a unit to the fixed wall member 52 and the door 39is opened by the operation of the pivot arm 30 and the link 41 to theposition shown by the dotted lines.

As above described, in operating the hydraulically operated door openingand closing device of the present invention, a pair of one-way reliefvalves are fitted to each of the opposing pistons interconnected by apiston rod reciprocating in the operating cylinder and an intermediateoil chamber is defined between said pistons to receive oil from thepressure oil chambers and reduce the excessive pressure in the hydraulicsystem, while a by-pass groove is provided on the cylinder wall tocontrol the flow of oil and to regulate the displacement speed of theopposing pistons in the operating cylinder. Moreover, according to thepresent opening and closing device, the pressure oil is circulated in aconfined path and the rotary pump and the motor for driving the same aremounted close to the operating cylinder and if an opposing force isimposed haphazardly on the door by someone using this device, part ofthe pressure oil will be circulated in a free state in the hydraulicsystem without undue drive force being produced thereby.

In the event that a person has his hand caught by the door, or hasbumped into the door accidentally, the hydraulic system operatessmoothly without undue force being exerted on any portion thereof, andpossible injury in such contingencies may be avoided. In addition,because of its compact size, the opening and closing device may befitted within a narrow space as in an automobile door frame.

What is claimed is:

1. A hydraulically operated opening and closing device for doors or thelike, comprising a cylinder, a pair of pistons interconnected by apiston rod reciprocable in said cylinder, a lug formed centrally of saidpiston rod, a bifurcated lever engaging at the forked end thereof withsaid lug formed on the piston rod and rigidly connected at the other endto one end of a rotatable shaft to rotate a lever which is secured atone end to said shaft and in turn is connected at its other end to adoor or the like, a rotary pump operative to build oil pressure in thecylinder and having a pair of discharge ports, each communicating with apair of pressure oil chambers formed between the opposite wall membersof the cylinder and said pistons, and a reversible type driving motoroperative to rotate said rotary pump reversibly, each of said pistonshaving a one-way control valve operative to discharge part of thepressure oil from one of said pressure oil chambers into an intermediateoil chamber formed in the cylinder by said pistons as percussive forceis applied to a piston from the side of said one of said pressure oilchambers, and another one-way control valve operative to reverse thepressure oil stored in the intermediate oil chamber under reducedpressure into said one of said pressure oil chambers.

2. A hydraulically operated opening and closing device for doors or thelike, as claimed in claim 1, wherein said rotary pump operative to buildhydraulic pressure in the cylinder is mounted on one end of saidcylinder and the reversible type motor operative to rotate said rotarypump reversibly is mounted in juxtaposition to said pump.

3. A hydraulically operated opening and closing device for doors or thelike, as claimed in claim 1, further comprising a cylinder of a shortlength mounted to one end of the first-mentioned cylinder andcommunicating therewith, a piston rod reciprocable in said short lengthcylinder and having a piston at one end thereof, and a manually operatedlever pivoted to the free end of said rod.

4. A hydraulically operated opening and closing device for doors or thelike, as claimed in claim 1, wherein said cylinder is formed with alongitudinal groove along the inner wall member thereof, said groovebeing operative to communicate one of said pressure oil chambers withsaid intermediate oil chamber as the piston is displaced in onedirection or the other and to discharge part of the pressure oiltherethrough to adjust the speed of displacernent of the pistons.

5. A hydraulically operated opening and closing device for doors or thelike, as claimed in claim 1, wherein an oil path connecting the pressureoil chambers to the discharge ports provided on the rotary pump isprovided with means to control the flow of oil discharged to said oilpath.

References Cited UNITED STATES PATENTS 1,120,833 12/1914 McElroy.

1,998,103 4/1935 Smith.

2,095,286 10/ 1937 Riach 60--52 2,900,791 8/1959 Kinsey 60-52 EDGAR W.GEOGHEGAN, Primary Examiner.

